Method and device for limiting the roll command of an aircraft as a function of a thrust asymmetry

Abstract

The device includes a calculation unit to automatically calculate an overall thrust moment of the engines which represents a thrust asymmetry of the engines of a multi-engine aircraft, a determination unit to automatically determine, using this overall moment, a maximum roll rate, and a limiting unit to automatically limit a roll command using this maximum roll rate.

1. A method for automatically managing roll piloting of a multi-engine aircraft, according to which method a roll command is generated, comprising:
 a) measuring on each of the engines of the aircraft, a value representative of a thrust of each engine; 
 b) converting each of the measured values into an effective thrust value for each engine; 
 c) calculating, from each of the effective thrust values, an overall thrust moment about a vertical axis of the aircraft, said overall thrust moment representing thrust asymmetry of the aircraft; 
 d) determining a maximum roll rate from the overall thrust moment, accounting for load level of a rear structure of the aircraft, in which the load level is based on roll rate and the thrust asymmetry, wherein the maximum roll rate corresponds to a maximum load level for the thrust asymmetry; and 
 e) limiting said roll command using said maximum roll rate. 
 
     
     
       2. The method as claimed in  claim 1 , further comprising f) applying said roll command to at least one roll control system of the aircraft. 
     
     
       3. The method as claimed in  claim 1 , wherein, in step a), for each engine, a value of a speed of the low pressure stage of said engine is measured. 
     
     
       4. The method as claimed in  claim 1 , wherein, in step a), for each engine, a position of a corresponding control lever is measured. 
     
     
       5. The method as claimed in  claim 1 , wherein, in step a) transmitted fault information relating to said engines of the aircraft is received. 
     
     
       6. A method for automatically managing roll piloting of a multi-engine aircraft, according to which method a roll command is generated, comprising:
 a) measuring on each of the engines of the aircraft, a value representative of a thrust of each engine; 
 b) converting each of the measured values into an effective thrust value for each engine; 
 c) calculating, from each of the effective thrust values, an overall thrust moment about a vertical axis of the aircraft, said overall thrust moment representing thrust asymmetry of the aircraft; 
 d) determining a maximum roll rate from the overall thrust moment, accounting for load level of a rear structure of the aircraft, in which the load level is based on roll rate and the thrust asymmetry, wherein the maximum roll rate corresponds to a maximum load level for the thrust asymmetry; and 
 e) limiting said roll command using said maximum roll rate, wherein 
 for an aircraft with electric flight controls, said roll command is expressed in a form of a roll rate and wherein, in step e), the roll rate is limited directly to said maximum roll rate. 
 
     
     
       7. A method for automatically managing roll piloting of a multi-engine aircraft, according to which method a roll command is generated, comprising:
 a) measuring on each of the engines of the aircraft, a value representative of a thrust of each engine; 
 b) converting each of the measured values into an effective thrust value for each engine; 
 c) calculating, from each of the effective thrust values, an overall thrust moment about a vertical axis of the aircraft, said overall thrust moment representing thrust asymmetry of the aircraft; 
 d) determining a maximum roll rate from the overall thrust moment, accounting for load level of a rear structure of the aircraft, in which the load level is based on roll rate and the thrust asymmetry, wherein the maximum roll rate corresponds to a maximum load level for the thrust asymmetry; and 
 e) limiting said roll command using said maximum roll rate, wherein 
 for an aircraft with manual flight controls, calculating, in step e), a limit deflection value δlmax of banking control surfaces is configured to act on the roll of the aircraft, using the following expression: δlmax=(K/V).pmax 
 in which: 
 K is a predetermined gain; 
 V is an aerodynamic speed of the aircraft; and 
 pmax is said maximum roll rate determined in step d), said limit deflection value calculated being applied to adjustable stops of said banking control surfaces. 
 
     
     
       8. A device for management of roll piloting of a multi-engine aircraft upon generating a roll command, comprising:
 control system that automatically measures , on each engine of the aircraft, a value representative of a thrust of each engine; 
 flight control computer that converts each of said measured values into an effective thrust value; 
 thrust moment calculating unit that automatically calculates, from the effective thrust values obtained for each engine, an overall thrust moment about a vertical axis of the aircraft, said overall thrust moment representing a thrust asymmetry of the aircraft; 
 maximum roll rate unit that automatically determines a maximum roll rate from the overall thrust moment, accounting for load level of a rear structure of the aircraft, in which the load level is based on roll rate and the thrust asymmetry, wherein the maximum roll rate, corresponds to a maximum load level for the thrust asymmetry; and 
 maximum roll rate unit that automatically limits said roll command using said maximum roll rate. 
 
     
     
       9. The device as claimed in  claim 8 , further comprising at least one roll control system of the aircraft. 
     
     
       10. An aircraft, further comprising the device of  claim 8 .